Instrument Error Tracking

PostHogOfficialCreated by PostHog

Skill
Tool integration
Data and AI
MIT
Low risk

From the author

Add PostHog error tracking to capture and monitor exceptions. Use after implementing features or reviewing PRs to ensure errors are tracked with stack traces and source maps. Also handles initial PostHog SDK setup if not yet installed.

— the description by PostHog

AutoGineer summary

Written by AutoGineer from the skill’s own files, not by the author

This skill provides a structured procedure for instrumenting your codebase with PostHog error tracking. It guides the agent through detecting your platform, installing the necessary SDK, enabling exception autocapture, and configuring manual error boundaries. It also ensures that environment variables are handled securely and that source maps are correctly configured for frontend and mobile projects, allowing for clear, actionable debugging.

What it does

Detects your project's platform and framework automatically.
Installs and initializes the PostHog SDK if not already present.
Enables automatic exception capture for unhandled errors.
Assists in adding manual error capture at critical boundaries.
Configures source map uploads for readable stack traces.
Sets up required environment variables for secure API communication.

When to use it

After implementing new features to ensure robust error monitoring.
During code reviews when you identify a need for better exception visibility.
When setting up a new project and wanting to include error tracking from the start.
When you need to resolve minified stack traces in your production logs.

Advantages

Ensures consistent error tracking patterns across different platforms.
Reduces manual setup effort by automating SDK installation and configuration.
Promotes secure practices by enforcing the use of environment variables.
Improves debugging efficiency by linking errors to original source code via source maps.

Usage examples

“Set up PostHog error tracking for my React project.”: The agent will detect the React environment, install the PostHog SDK, enable autocapture, and guide you through setting up the necessary environment variables.
“I need to track errors in my Node.js backend using PostHog.”: The agent will identify the Node.js environment, configure the SDK, and help you place manual capture points in your catch blocks.

Install

Download the skill as a ZIP:
https://mp-staging.autogineer.com/agent-skills/posthog/instrument-error-tracking/download

Unzip it into the cross-client skills folder of your project:

mkdir -p .agents/skills && unzip instrument-error-tracking.zip -d .agents/skills

Documentation by PostHog

Add PostHog error tracking

Use this skill to add PostHog error tracking that captures and monitors exceptions in your application. Use it after implementing features or reviewing PRs to ensure errors are tracked with full stack traces and source maps. If PostHog is not yet installed, this skill also covers initial SDK setup. Supports any platform or language.

Supported platforms: React, Next.js, Web (JavaScript), Node.js, Python, PHP, Ruby, Ruby on Rails, Go, Elixir, Angular, Svelte, Nuxt, React Native, Flutter, iOS, Android, and Hono.

Instructions

Follow these steps IN ORDER:

STEP 1: Analyze the codebase and detect the platform.

Look for dependency files (package.json, pubspec.yaml, Podfile, Package.swift, requirements.txt, go.mod, Gemfile, composer.json, mix.exs, etc.) to determine the language and framework.

Look for lockfiles (pnpm-lock.yaml, package-lock.json, yarn.lock, bun.lockb, go.sum, pubspec.lock, Podfile.lock, Package.resolved, mix.lock) to determine the package manager.

Check for existing PostHog setup (SDK initialization, env vars, etc.). If PostHog is already installed and initialized, skip to STEP 4.

STEP 2: Research instrumentation. (Skip if PostHog is already set up.) 2.1. Find the reference file below that matches the detected platform — it is the source of truth for SDK initialization, exception autocapture, and framework-specific error tracking patterns. Read it now. 2.2. If no reference matches, fall back to your general knowledge and web search. Use posthog.com/docs as the primary search source.

STEP 3: Install and initialize the PostHog SDK. (Skip if PostHog is already set up.)

Add the PostHog SDK package for the detected platform. Do not manually edit package.json — use the package manager's install command.
Follow the framework reference for where and how to initialize.

STEP 4: Enable exception autocapture.

Follow the platform reference to enable exception autocapture. This automatically captures unhandled exceptions without additional code.

STEP 5: Add manual error captures.

Identify error boundaries, catch blocks, and critical user flows where errors should be explicitly captured.
Add posthog.captureException() or the platform-equivalent at these locations.
Do not alter the fundamental architecture of existing error handling. Make additions minimal and targeted.
You must read a file immediately before attempting to write it.

STEP 6: Upload source maps (frontend/mobile only).

Configure source map uploads so stack traces resolve to original source code, not minified bundles.
Follow the platform-specific reference for upload configuration (build plugins, CI scripts, etc.).

STEP 7: Set up environment variables.

Check if the project already has PostHog environment variables configured (e.g. in .env, .env.local, or framework-specific env files). If valid values already exist, skip this step.
If the PostHog project token is missing, use the PostHog MCP server's projects-get tool to retrieve the project's api_token. If multiple projects are returned, ask the user which project to use. If the MCP server is not connected or not authenticated, ask the user for their PostHog project token instead.
For the PostHog host URL: check the projects-get MCP response for a region field — US maps to https://us.i.posthog.com, EU maps to https://eu.i.posthog.com. If the region is not available from the MCP response or from existing project configuration, ask the user: "Are you on PostHog US Cloud or EU Cloud?" Do not assume US Cloud.
Write these values to the appropriate env file using the framework's naming convention.
Reference these environment variables in code instead of hardcoding them.

STEP 8: Verify and clean up.

Check the project for errors. Look for type checking or build scripts in package.json.
Ensure any components created were actually used.
Run any linter or prettier-like scripts found in the package.json, but ONLY on the files you have edited or created during this session. Never run formatting or linting across the entire project's codebase.

Reference files

references/react.md - React error tracking installation
references/web.md - Web error tracking installation
references/nextjs.md - Next.js error tracking installation
references/node.md - Node.js error tracking installation
references/python.md - Python error tracking installation
references/django.md - Django
references/flask.md - Flask
references/php.md - Php error tracking installation
references/laravel.md - Laravel
references/ruby.md - Ruby error tracking installation
references/ruby-on-rails.md - Ruby on rails error tracking installation
references/ruby-on-rails.md - Ruby on rails
references/go.md - Go error tracking installation
references/dotnet.md - .net error tracking installation
references/dotnet.md - .net
references/elixir.md - Elixir error tracking installation
references/angular.md - Angular error tracking installation
references/svelte.md - Sveltekit error tracking installation
references/nuxt-3-7.md - Nuxt error tracking installation (v3.7 and above)
references/nuxt-3-6.md - Nuxt error tracking installation (v3.6 and below)
references/react-native.md - React native error tracking installation
references/flutter.md - Flutter error tracking installation
references/ios.md - Ios error tracking installation
references/android.md - Android error tracking installation
references/hono.md - Hono error tracking installation
references/fingerprints.md - Fingerprints
references/alerts.md - Send error tracking alerts
references/monitoring.md - Monitor and search issues
references/assigning-issues.md - Assign issues to teammates
references/upload-source-maps.md - Upload source maps
references/COMMANDMENTS.md - Framework-specific rules the integration must follow

Each platform reference contains SDK-specific installation and manual capture patterns. Find the one matching the user's stack.

Key principles

Environment variables: Always use environment variables for PostHog keys. Never hardcode them.
Minimal changes: Add error tracking alongside existing error handling. Don't replace or restructure existing code.
Autocapture first: Enable exception autocapture before adding manual captures.
Source maps: Upload source maps so stack traces resolve to original source code, not minified bundles.
Manual capture for boundaries: Use captureException() at error boundaries and catch blocks for errors that don't propagate to the global handler.

Files

ATTRIBUTION.mdAdded by AutoGineer961 B
LICENSELicence file added by AutoGineer1.0 KiB
SKILL.md6.9 KiB
references/COMMANDMENTS.md1.5 KiB
references/alerts.md4.2 KiB
references/android.md4.8 KiB
references/angular.md9.1 KiB
references/assigning-issues.md6.8 KiB
references/django.md14.9 KiB
references/dotnet.md25.8 KiB
references/elixir.md10.0 KiB
references/fingerprints.md4.6 KiB
references/flask.md8.1 KiB
references/flutter.md13.3 KiB
references/go.md5.9 KiB
references/hono.md3.7 KiB
references/ios.md7.4 KiB
references/laravel.md13.1 KiB
references/monitoring.md8.7 KiB
references/nextjs.md15.8 KiB
references/node.md4.8 KiB
references/nuxt-3-6.md5.9 KiB
references/nuxt-3-7.md5.3 KiB
references/php.md6.4 KiB
references/python.md9.0 KiB
references/react-native.md10.4 KiB
references/react.md6.4 KiB
references/ruby-on-rails.md19.7 KiB
references/ruby.md3.6 KiB
references/svelte.md5.8 KiB
references/upload-source-maps.md4.2 KiB
references/web.md5.8 KiB

references/flask.md

AI agents: this is one page from PostHog's docs. Full index of Markdown docs for LLMs: https://posthog.com/llms.txt

Flask

Canonical URL: https://posthog.com/docs/libraries/flask

Cloud region: This page uses US Cloud hosts. For an EU Cloud project, use https://eu.i.posthog.com instead of https://us.i.posthog.com (ingestion host), and use https://eu.posthog.com instead of https://app.posthog.com (app host for links).

Install with the wizard

Run this command in your project directory to add PostHog to your Flask project. The wizard detects your framework, installs the SDK, and sets up your first events.

npx @posthog/wizard

Or set it up manually by following the rest of this guide.

Installation

To start, run pip install posthog to install PostHog’s Python SDK.

Then, initialize PostHog where you'd like to use it. For example, here's how to capture an event in a simple route:

app.py

from flask import Flask
from posthog import Posthog

app = Flask(__name__)

posthog = Posthog(
    '<ph_project_token>',
    host='https://us.i.posthog.com',
)

@app.route('/api/dashboard', methods=['POST'])
def api_dashboard():
    posthog.capture(
        'dashboard_api_called',
        distinct_id='distinct_id_of_your_user',
    )
    return '', 204

You can find your project token and instance address in your project settings.

Identifying users

Identifying users is required. Backend events need a distinct_id to associate events with the correct user.
In Python, you can do this through a context. All event captures in the same context will be tagged automatically with the correct distinct_id. Typically, you would set a fresh context and identify at the top of each route.
from posthog import new_context, identify_context, capture

@app.get("/foo")
def foo(current_user: User = Depends(get_current_user)):
    with new_context(): # Set context at the top of a route
        identify_context(current_user.id)
        capture("foo_viewed")
    return {"status": "ok"}
When possible, write a small piece of middleware that resolves your authenticated user, wrap a context around the request, and identifies it. Every capture() downstream is then attributed automatically. The SDK's Django middleware does this automatically and you can replicate it when using the plain Python SDK.

Request contexts

Version 7.69.0 and later of the Python SDK includes a Flask integration that creates a fresh context for every request. It adds the request URL, method, path, route, IP address, and user agent to events captured during the request.

app.py

from posthog.integrations.flask import PosthogFlaskIntegration

PosthogFlaskIntegration(
    app,
    client=posthog,
    capture_exceptions=True,
)

Setting capture_exceptions=True captures unhandled Flask exceptions. Set it to False for request enrichment without automatic exception capture. If you omit it, the integration inherits the client's enable_exception_autocapture setting.

You can also provide:

request_filter to skip both enrichment and automatic exception capture for selected requests
extra_properties to add application-specific properties to the request context
trust_tracing_headers to accept PostHog session and distinct ID headers

If you're using PostHog JavaScript Web on the frontend, configure tracing_headers for your Flask backend hostname so browser requests include the session and distinct ID headers.

The integration ignores these headers by default because clients can control them. Set trust_tracing_headers=True when registering the integration to accept them as analytics context. Don't use them for authentication or authorization.

Identify the request context from your route when you have an authenticated user ID:

from flask import session
from posthog import identify_context

@app.route("/api/dashboard", methods=["POST"])
def api_dashboard():
    user_id = session.get("user_id")
    if user_id:
        identify_context(str(user_id))

    posthog.capture("dashboard_api_called")

    return "", 204

Events captured without a context or explicit distinct_id are sent as anonymous events with an auto-generated distinct_id. See the Python SDK docs for more details.

Error tracking

PosthogFlaskIntegration captures unhandled exceptions when you set capture_exceptions=True or enable exception autocapture on its client. It doesn't capture expected HTTP exceptions or exceptions consumed by your application's error handlers.

Call capture_exception() from a custom error handler when you want to report a handled exception:

from flask import Flask, jsonify
from posthog import Posthog

app = Flask(__name__)
posthog = Posthog('<ph_project_token>', host='https://us.i.posthog.com')

@app.errorhandler(Exception)
def handle_exception(e):
    # Capture methods, including capture_exception, return the UUID of the captured event,
    # which you can use to find specific errors users encountered
    event_id = posthog.capture_exception(e)

    # You can show the event ID to your user, and ask them to include it in bug reports
    response = jsonify({'message': str(e), 'error_id': event_id})
    response.status_code = 500
    return response

Next steps

For any technical questions for how to integrate specific PostHog features into Flask (such as analytics, feature flags, A/B testing, etc.), have a look at our Python SDK docs.

Alternatively, the following tutorials can help you get started:

Supported versions

These docs cover version 7.x of the PostHog Python SDK, which requires Python 3.10 or higher. Python 3.9 is no longer supported on 7.x.x and higher — pin to the 6.x line with pip install 'posthog<7', where 6.9.3 is the final release.

Everything on this page works the same way on 6.9.3. Event capture, the context API (new_context, identify_context, set_context_session), and PosthogContextMiddleware are identical on 6.9.3 and 7.0.0 — 7.0.0 only dropped Python 3.9 and bumped the optional LLM provider SDKs. That includes the middleware identifying the request context from the X-POSTHOG-DISTINCT-ID header and falling back to the authenticated user, which behaves the same across both lines.

Later 7.x releases add what the 6.x line does not receive, such as the Celery integration, tracing header sanitization, and set_context_device_id. They also changed the middleware's own captured properties: 7.x sends the request IP as $ip, where 6.9.3 sends it as $ip_address, and 7.x additionally captures $request_path, $raw_user_agent, and the authenticated user's email.

Requirements and compatibility

Works with: Claude Code, Claude apps, OpenAI Codex, GitHub Copilot, Cursor, Gemini CLI, Kiro, OpenCode, Goose, Amp, Roo Code, JetBrains Junie, Factory Droid, Devin (ex-Windsurf), Mistral Vibe, OpenHands, Letta

“Works with” means the tool reads the open Agent Skills format; a skill written for one tool may use features others lack.

Needs: Needs an MCP server, Needs Python, Needs Node.js

Security

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Attribution and licence

Created by

PostHog

Publisher

PostHog (Official)

Source

PostHog/skills · skills/omnibus/instrument-error-tracking · commit a5d30e7

Licence

MIT License (redistribution allowed)

LICENSE (added by AutoGineer from LICENSE)
ATTRIBUTION.md (written by AutoGineer)

Synced

2026-11-08

AutoGineer is not affiliated with or endorsed by PostHog.

Download ZIP

The ZIP holds the skill’s files, its licence files and an ATTRIBUTION.md. Download instrument-error-tracking.zip